Horticulturists and landscape designers match plants to the light conditions they need, but consumers can be confused by terms on plant tags citing those conditions. What is “full sun,” “partial sun,” or “dry shade?” Furthermore, light conditions are not just the hours of light but its intensity and the direction from which it comes. Light changes with the seasons and over time with the maturity of the plants. Hence, the planning of gardens requires observing, measuring, and mapping the light the landscape receives each season. Experts advise going outside every hour from dawn to dusk to observe and map which areas have sun or shade. Total the number of hours each area has sun or shade to discover which light conditions exist.
The consensus of sources use these classifications:
•Full sun is six or more hours of direct sun per day. It may not be continuous with four hours in the morning and three to four in the afternoon.
•Partial sun is between four to six hours of direct sun per day.
•Partial shade is two to four hours of sun per day sheltered from harsh afternoon sun.
•Shade is less than two hours of sunlight per day.
•Dry shade is an area where rainfall is prevented from reaching the ground due to dense tree canopy or roof overhangs.
•Dappled or filtered shade is a mix of sun and shade through vegetation.
Mapping light conditions assists plant selection and placement. A spring webinar hosted by the National Garden Bureau featured two floriculture companies, Dummen Orange and Walter’s Gardens, Inc., presenting new shade perennial introductions.
Aralia cordata ‘Sun King’ is a bright golden to chartreuse-leafed 3’ tall plant for partial shade.
Astilbe ‘Dark Side of the Moon’ has deep chocolate burgundy leaves and dark stems with raspberry buds that explode with rosy purple flowers. It requires partial or dappled shade.
Brunneria macrophylla ‘Jack of Diamonds’ with huge 9-10” silvery leaves with green veins and baby blue flowers thrives in shade with consistently moist soil.
Epimedium ‘Amber Queen’ with long sprays of delicate jester hat-like yellow orange flowers in spring conquers dry shade.
Helleborus ‘Paris in Pink’ blooms in late winter and is perfect for naturalizing in moist shady woodlands where the root system can spread.
Heuchera ‘Wildberry’ has large, scalloped, glossy purple leaves with dark stems bearing rosy pink calyxes and white flowers. This native North American plant adapts to full sun or full shade and attracts bees, butterflies, and hummingbirds.
Hosta ‘Time in a Bottle’ flaunts chartreuse rippled foliage and deep purple flowers in the summer shade garden.
Laminum maculata ‘Golden Anniversary’ is a dry shade tolerant groundcover with heart-shaped leaves edged in gold and rosy-purple flowers attracting pollinators.
Phlox ‘Woodlander Lilac’, a creeping evergreen adaptable to partial shade or full sun, flowers profusely and continuously for weeks each spring forming a thick carpet of lilac flowers enticing bees and butterflies.
Pulmonaria ‘Spot On’ with silver speckled foliage and pink spring flowers grows best in filtered sun or part shade.
These shade perennials were grown in trial gardens from Miami, Fla. to Winnipeg, MB to gather data on overall performance. All match Columbia’s hardiness zone 8.
Leave a Reply